FIG. 25 illustrates a conventional LED lamp 900. The LED lamp 900 as shown in FIG. 25 includes a substrate 901 and a plurality of LED modules 902 mounted thereon. The LED lamp 900 may be used as a substitute for, for example, a mercury lamp. Each LED module 902 includes an LED chip 903 and a case 904. The LED chip 903 is mounted on the case 904. A mount electrode (not shown) is installed in the case 904. The LED module 902 configured as above is subjected to a heating treatment at a predetermined temperature within a reflow furnace, for example, under a condition where the mount electrode is temporarily bonded to a wiring pattern (not shown) of the substrate 901 by means of solder paste, which is called “surface mounting.”
Mercury lamps are installed on a ceiling of a building such as a gymnasium or the like, in which case an illumination target is a floor of the gymnasium. When the LED lamp 900 is used for the same purpose, it is required to illuminate the gymnasium floor more uniformly from end to end. However, it is difficult for the LED lamp 900 to provide uniform illumination since the plurality of LED modules 902 is discretely arranged.